Bridgestone Motorcycle Parts Discussion Board

Bridgestone Tech Talk => Restoration => Topic started by: greg145 on September 29, 2013, 11:36:43 PM

Title: 1970 GP 100 Restoration
Post by: greg145 on September 29, 2013, 11:36:43 PM
I spoke of what I intend to do to this thing in the introductions page.  Basically get it running and make it look respectable, not show quality or anything.  It was laid over on the right side and I'm gonna need new handlebars, carb cover, rotary valve cover, need to fix one of my front shocks, maybe replace some bearings here and there, it also needs an exhaust which the previous owner said he might have, but I suspect might be mangle being that the exhaust is on the right side and that's the side that the bike was laid down on.  The bike has been in a barn for at least 30 years, probably more.  The paint has been sun damaged and is peeling badly on some of the painted parts.  I will probably redo the wiring if its doable.  Clean the carb and give the engine a good once over, I don't think it will need much, but obviously I want to get it running and see what I've got.  Any other ideas I would appreciate.  How expensive are parts?  Are they reasonable?

Here are some pics.
Title: Re: 1970 GP 100 Restoration
Post by: greg145 on September 29, 2013, 11:40:28 PM
More pictures
Title: Re: 1970 GP 100 Restoration
Post by: greg145 on September 29, 2013, 11:45:05 PM
I can't blame the mouse that lived in the air filter, that'd make a nice and warm winter home..... :)
Title: Re: 1970 GP 100 Restoration
Post by: greg145 on September 30, 2013, 06:45:48 PM
This is where I'm at now after tearing everything down...
Title: Re: 1970 GP 100 Restoration
Post by: greg145 on September 30, 2013, 06:49:54 PM
Two more
Title: Re: 1970 GP 100 Restoration
Post by: greg145 on October 01, 2013, 11:18:55 PM
Another question..... My bike has 5600 miles on it.  I'm obviously going to go through the carb, etc to get the engine running, but now I am considering looking into the engine a little bit deeper.  Are there any issues that those engines typically have?  Do you have any ideas of what I should specifically do to the engine?  Suggestions please!!!!!!!!  I consider myself to have above average mechanical competency, so I would feel comfortable doing most engine work.  I am not looking to do any engine modifications or anything of that nature.  Your responses are greatly appreciated and I value your opinion.  Thanks!
Title: Re: 1970 GP 100 Restoration
Post by: disc_valve on October 04, 2013, 06:18:45 AM
Hi,

Thats a nice jig-saw puzzle you've to reassemble. Actually, it doesn't look in too bad condition. The BS90/100 engine is pretty bullet proof, and the only points I can think of to check are the cylinder bore (check for plating bubbled or lifting), the piston ring pegs (which can wear quickly) and I believe that the plastic oli pump drive gear can sometimes crack. Otherwise, it's probabl;y worth putting in new bearings and seals (which Richard probably has in stock).

Good luck!

Graham
Title: Re: 1970 GP 100 Restoration
Post by: greg145 on October 05, 2013, 04:27:24 PM
Interesting you said something about the oil pump drive gear, I noticed it has a few hairline cracks in it.  I will replace that, check the cylinder bore and piston ring pegs, and look into those seals and bearings.  Currently the carb is soaking in some carb cleaner, going to get that cleaned up and put back together.  Also, on the docket is taking the frame and some of the other parts to the car wash to get them cleaned up and everything.
Title: Re: 1970 GP 100 Restoration
Post by: greg145 on November 19, 2013, 08:29:15 PM
Haven't posted in a while.  I've cleaned up a lot of the parts, pressure washed the frame and washed up some of the chrome pieces, etc.  I soaked the carb, and have it put back together for now and have all or most of the grease/grime/gunk off the engine.  I have also started to tear the engine apart.  I have pulled the head and now the jug off of the engine.  I am hoping to get a bunch of engine parts for Christmas and get the engine going ASAP. Let me know what you think.  Any ideas?  I am trying to figure out what to do with some of the chrome, which is pretty heavily rusted.  Any ideas?
Title: Re: 1970 GP 100 Restoration
Post by: greg145 on November 19, 2013, 08:34:55 PM
Anyone notice anything from these pictures that you think needs done to the engine? I am going to put rings in it.
Title: Re: 1970 GP 100 Restoration
Post by: greg145 on August 18, 2014, 09:47:49 PM
Got back up on the wagon this week. Parts have been sitting in the basement for a while. I got a new piston, rings, head gaskets and carb gasket for Christmas. I just got done installing all of those yesterday. I also removed the rotary valve cover yesterday. I need to order a new one because the tube that is a part of the rotary valve cover that the carb bolts to got broken off by the previous owner.  There is some sort of seal that was galded onto the carb, where the carb bolts onto the rotary valve cover. I need to replace the seal, but can't seem to find it in the parts manuals. It almost felt plastic when I was chipping it out of the carb. It was ver hard. Any ideas? 
Title: Re: 1970 GP 100 Restoration
Post by: CL-100 on August 19, 2014, 03:17:37 PM
I finished restoring a GP100 earlier this year and don't recall the seal you're describing.  My carb just slipped onto the spigot for the rotary valve cover and hasn't been a problem.  If you look on the parts manual page for "crankcase A", there are some seals there in the area you're describing.  If this isn't what you're trying to identify, could you post a picture?  Thanks, hope you figure it out.
Title: Re: 1970 GP 100 Restoration
Post by: CL-100 on August 19, 2014, 03:51:48 PM
I just reread your post again and was wondering if the pieces you were "chipping out of the carburetor" are the spigot portion of the rotary valve cover?
Title: Re: 1970 GP 100 Restoration
Post by: dcr on August 19, 2014, 04:19:56 PM
That is part of the carb and not a separate item in the parts manual.
Title: Re: 1970 GP 100 Restoration
Post by: grundlegrabber on August 19, 2014, 09:52:12 PM
Isn't there a bakelite insert in the carb spigot? If so, that is part of the carb. Not a part that you can buy. Really like the 100GP and 100 TMX models Nice to see you are putting that old barn bike back together.
Title: Re: 1970 GP 100 Restoration
Post by: greg145 on August 20, 2014, 05:26:05 PM
It definitely was not the spigot part of the RVC, I have that piece, it broke off, and it was metal. The piece I chipped out was busted up already, but it was definitely some type of plastic, probably that bakelite grabber talked about. If that is what it is, will I need to buy a whole new carb or can I use something similar to the Bakelite when I fasten the carb onto the spigot of the RVC?  I have no photos of the stuff I chipped out. Sorry.
Title: Re: 1970 GP 100 Restoration
Post by: greg145 on August 20, 2014, 05:34:25 PM
Any idea on the cost of a rotary valve cover? I e-mailed the powers that be about pricing on a few different parts and have yet to hear back.